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Patentes

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Número de publicaciónUS4734742 A
Tipo de publicaciónConcesión
Número de solicitudUS 06/933,663
Fecha de publicación29 Mar 1988
Fecha de presentación21 Nov 1986
Fecha de prioridad21 Nov 1986
TarifaPagadas
Número de publicación06933663, 933663, US 4734742 A, US 4734742A, US-A-4734742, US4734742 A, US4734742A
InventoresRobert C. Klumpp, Frederick B. Messbauer, Donald C. Buch
Cesionario originalEastman Kodak Company
Exportar citaBiBTeX, EndNote, RefMan
Enlaces externos: USPTO, Cesión de USPTO, Espacenet
Duplex scanner
US 4734742 A
Resumen
An electrooptical scanner includes an optical system having mirrors for directing light from one side of a document through a lens to a charge coupled device and from the other side of the document through the same lens to a different charge coupled device. The scanner scans both sides at the same time using a straight paper path.
Imágenes(2)
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Reclamaciones(7)
We claim:
1. A duplex scanner having:
a lens;
first and second exposure stations positioned to receive a document with the stations facing opposite sides of a document so received;
means for directing light from one side of a received document at the first station along a first optical path through said lens to a first electrooptical sensor in an image plane of the lens, and for directing light from the other side of the document at the second station along a second optical path through said lens to a second electrooptical sensor in an image plane of the lens, said electrooptical sensors being of the type having separately electronically addressable image sensing picture elements; and
means for effecting relative movement between the light directing means and a received document.
2. A duplex scanner according to claim 1 wherein the exposure stations, in at least one mode of operation, are stationary and the means for effecting relative movement includes means for feeding a document along a generally straight line document path located between the stations.
3. A duplex scanner according to claim 2 having a second mode of operation in which the portion of said light directing means which directs light along said second optical path, said lens and said second electrooptical sensor are movable as a unit to traverse a stationary object to direct light from such stationary object to said second sensor.
4. A duplex scanner according to claim 1 wherein the lens is oriented with its optical axis generally orthogonal to the direction of relative movement between the exposure stations and a received document.
5. A duplex scanner according to claim 4 wherein the lens is orineted with its optical axis in a plane generally parallel to a received document.
6. A scanner having at least one exposure station, means for directing light from one side of a document received by said exposure station through a lens to an electrooptical sensor, means for feeding a document along a document feed path past said exposure station, and means for directing light along a skew sensing optical path from a position along the path of movement of a document through the lens to a skew sensing electrooptical sensor in an image plane of the lens to monitor the orientation of the leading edge of a document fed along said document feed path.
7. A duplex scanner having:
a lens;
first and second exposure stations positioned to receive a document with the stations facing opposite sides of a document so received;
means for directing light from one side of a received document at the first station along a first optical path through said lens to a first electrooptical sensor in an image plane of the lens, and for directing light from the other side of the document at the second station along a second optical path through said lens to a second electrooptical sensor in an image plane of the lens;
means for feeding a document along a generally straight line document path located between the stations; and
means for directing light along a third optical path from a position along the path of movement of a document, through the lens to a third electrooptical sensor in an image plane of the lens to monitor the orientation of the leading edge of a document fed along said document path.
Descripción

This invention relates to optical scanners, and more specifically to a scanner capable of projecting images of opposite sides (duplex) of a document sheet onto electrooptical sensing means.

The output of optical scanners is used by a variety of types of devices, of which printers is only one. Although the problem giving rise to this invention is described in terms of a copier (a printer plus a scanner), the invention is usable in other applications of scanners as well.

Copiers presently on the market automatically expose opposite sides of a document by turning the document over between exposures at the same exposure station. The turnover mechanism is expensive, is a source of paper jams and can be the speed limiting aspect of an entire copying system.

U.S. Pat. Nos. 4,261,661, 4,247,192, and 3,980,406 show optical systems in which narrow line images of opposite sides of a moving document are sequentially projected onto moving light-sensitive material from exposure stations that are separate for the opposite sides. At least partially separate stationary optics are used for the respective stations, but document turnover or similar mechanisms are nevertheless employed. In several such systems a portion of the optical system is also movable for scanning a stationary object such as a book.

U.S. Pat. No. 3,936,171 shows a copier in which images of opposite sides of a document are projected virtually simultaneously using a straight through paper path. The images are projected by entirely separate optics onto separate photoconductive imaging drums. This system offers an increase in speed and a straight through paper path at the expense of an extra copying drum and accessories.

U.S. Pat. No. 3,885,871 shows an optical system for imaging opposite sides of serially fed documents onto film using two sets of mirrors and a single lens.

Optical exposing systems such as these are being replaced in copying by electrooptical scanning devices in which an electrooptical element having separately electronically addressable image sensing pixels, such as a linear CCD (charge-coupled device) receives a line scan of a document to create an electronic signal representative of the document. See, for example, U.S. Pat. No. 4,506,301. With such systems, ordinary duplex scanning would involve turning the document over between scans.

It is an object of this invention to provide a scanner of the type having a linear CCD or other similar electrooptical sensor which scanner is capable of scanning both sides of a given document without turning the document over.

This object is accomplished by a duplex scanner having means for directing scanning illumination along first and second optical paths from opposite sides of a document onto separate electrooptical sensors.

With separate sensors, both sides of the document can be scanned at the same time, greatly increasing speed as compared with consecutively scanning each side with the same sensor.

An advantage of scanning the opposite sides of the same document with at least partially separate optics is that the document does not have to be turned over. This eliminates the necessity of a costly turnover mechanism, reduces paper handling and paper jams. According to a preferred embodiment of the invention, the document is fed along a "straight through" paper path, with path lends itself to low cost and reliability.

According to another preferred embodiment of the invention, the optical system directs the images back through the same lens to the sensors, each located in an image plane of the lens. The advantage of using the same lens while doing such duplex scanning is that you save the substantial added expense of a separate lens for each side.

According to another preferred embodiment of the invention, the lens has an optical axis generally orthogonal to the direction of travel of the documents being scanned and lying in a plane generally parallel to the document itself. This construction lends itself to compactness and to a minimum of reflecting surfaces.

According to another preferred embodiment of the invention the second optical path, the lens and at least one sensor are movable for scanning a stationary object, for example, a book placed on an exposure platen.

According to another preferred embodiment of the invention a third electrooptical sensor is placed in the image plane of the lens and a third optical path is provided from a location on the path of movement of the document to that third sensor to monitor the orientation and thereby detect any skew in the document as fed. Such detection can be used to signal an operator or to actuate a mechanical mechanism for correcting for such skew.

FIGS. 1 and 2 are schematic front and side views respectively of a duplex scanner constructed according to the invention.

FIG. 3 is a schematic front view of another embodiment of the invention in which an optical system for scanning a stationary object such as a book is added to the duplex scanner shown in FIGS. 1 and 2.

According to FIGS. 1 and 2, a lens 1 has an image plane containing three electrooptical image sensors having separately electronically addresable pixels, for example, linear CCD's 2, 3 and 4. CCD 2 receives light directed from a first exposure station 25 along a first optical path 22 by mirrors 7 and 8. Exposure station 25 includes lamps 16 and 17 cooperating with reflectors 18 and 19.

CCD 4 receives light directed from a second exposure station 24 along a second optical path 21 by mirrors 5 and 11. Exposure station 24 includes lamps 14 and 15 cooperating with reflectors 12 and 13.

First and second exposure stations 25 and 24 are oriented so that images of opposite sides of a received document are projected at substantially the same time by lens 1 on CCD's 2 and 4. Optical paths 21 and 22 therefore project in generally opposite directions from the document and then are folded by mirrors 5, 7, 8 and 11 back through lens 1.

CCD 3 receives light along a light path 23 directed by mirros 6, 9 and 10 from a position 30 near exposure stations 25 and 24 through the lens 1.

In operation a document is fed along a document path 20 by rollers 26, 27, 28 and 29 past position 30 and exposure stations 24 and 25. As the document passes exposure station 25, an image of the bottom side of the moving document is projected onto CCD 2. As the document passes exposure station 24, an image of the top side of the document is projected onto CCD 4. As the document passes point 30, the orientation of the front edge of the document is sensed by CCD 3. The mirrors are arranged so that all the light paths are directed through lens 1 with lens 1 oriented with its optical axis substantially orthogonal to the direction of motion of the document and lying in a plane roughly parallel to the document itself. This provides a very compact arrangement for scanning both sides of the document at substantially the same time with a minimum of reflecting surfaces, and with substantial cost savings associated with using the same lens.

The use of separate sensors 2 and 4 allows both sides of the document to be scanned at the same time. This essentially doubles the output of an ordinary scanner which would scan the two sides consecutively onto the same sensor, even assuming any document turn around time can be eliminated in the latter structure. The output of the sensors are electronic signals which can be fed into separate memories and read out by a printer, a facsimile apparatus, a computer terminal or the like. If both the scanner and, for example, a printer are executing the same job at the same time, using a one page buffer, the printer can operate at twice the speed of the document feed portion of the scanner.

Thus, this scanner at least doubles the speed of an ordinary scanner at the cost of several reflecting surfaces and an extra linear CCD. The cost of the latter has become a small fraction of its cost a few years ago.

This structure also has the advantages associated with a straight through paper path of greatly reducing the problems associated with paper jams and the expense associated with turnover mechanisms and the like. Thus, the invention provides increased reliability as well as reduction in parts.

FIG. 3 shows the same optical system as FIGS. 1 and 2 with the added feature that mirrors 6, 7, 8, 9 and 10, lens 1, illumination lamps 16 and 17, reflectors 18 and 19 and CCD's 2, 3 and 4 are all movable together to scan a stationary document or object, for example, a book placed on an exposure platen 31.

In the FIG. 3 embodiment, the elements defining optical path 23 are also movable, reading the first edge encountered in the scanning process, the right edge of the book shown in FIG. 3.

The location of the lens in a direction orthogonal to the direction of movement of the document again allows easy access to light paths from opposite sides of the document while providing clearance between the document and those optical paths. In the FIG. 3 embodiment, this lens orientation permits movement of a portion of that optical system without also interfering with the stationary document.

CCD 3 senses the skew of the document in both the FIGS. 1 and 2 embodiment and the FIG. 3 embodiment. In the FIGS. 1 and 2 embodiment this can be used to mechanically correct for such skew as is well known in the art, see, for example, U.S. Pat. No. 4,310,236. In both embodiments the output of CCD 3 can be used to electronically correct for the skew by electronically rotating the document by the use of appropriate logic, see, for example, U.S. Pat. No. 4,558,461. The output of CCD 3 can also be used to signal the operator that there is a skew in the document.

The invention has been described in detail with particular reference to a preferred embodiment thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

Citas de patentes
Patente citada Fecha de presentación Fecha de publicación Solicitante Título
US3637302 *19 Jul 196825 Ene 1972Pelorex CorpCompact copying machine with multiple-function reciprocating carriage
US3885871 *12 Abr 197427 May 1975IbmDocument photography system
US3936171 *11 Mar 19743 Feb 1976Xerox CorporationElectrostatographic methods and apparatus
US3980406 *2 Jun 197514 Sep 1976Xerox CorporationDuplex imaging system
US3981580 *5 Nov 197421 Sep 1976Ricoh Co., Ltd.Method and a system for concurrently copying both sides of an original
US4110030 *14 May 197629 Ago 1978Canon Kabushiki KaishaElectrostatic copying apparatus
US4247192 *23 Oct 197827 Ene 1981Canon Kabushiki KaishaCopying machine
US4261661 *6 Abr 197914 Abr 1981Agfa-Gevaert N.V.Apparatus for producing double sided copies
US4506301 *12 Oct 197919 Mar 1985Xerox CorporationMultiple mode raster scanner
US4571636 *21 Dic 198318 Feb 1986Fuji Xerox Co., Ltd.Device for reading images of both surfaces of an original in one pass
US4616269 *23 Sep 19857 Oct 1986Fuji Xerox Co., Ltd.Document reader
US4673285 *23 May 198616 Jun 1987Xerox CorporationOptical scanning of duplex documents
JPS6070436A * Título no disponible
JPS55153964A * Título no disponible
JPS59123833A * Título no disponible
Otras citas
Referencia
1 *Xerox Disclosure Bulletin, vol. 8, No. 3, May/Jun. 1983, p. 263.
Citada por
Patente citante Fecha de presentación Fecha de publicación Solicitante Título
US5136665 *6 Nov 19914 Ago 1992Canon Kabushiki KaishaTwo-sided original reading apparatus
US5280321 *8 Sep 199218 Ene 1994Eastman Kodak CompanyDual roll rotary microfilmer for 25x reduction or less
US5298937 *4 Ene 199329 Mar 1994Eastman Kodak CompanyHigh productivity method and apparatus for scanning simplex or duplex originals
US5463451 *15 Nov 199431 Oct 1995Xerox CorporationDocument reproduction system including a duplex document handler with natural inversion
US5467164 *21 Jun 199314 Nov 1995Bell & Howell Document Management Products CompanyDocument processing system having a straight line document path
US5488485 *3 Abr 199530 Ene 1996Canon Kabushiki KaishaImage reading apparatus
US5610682 *3 Ene 199511 Mar 1997Hirakawa Kogyo Sha Co., Ltd.Photographing method and photosensitive material printing apparatus utilizing the same
US5646744 *11 Ene 19968 Jul 1997Xerox CorporationShow-through correction for two-sided documents
US5828469 *21 Mar 199727 Oct 1998Xerox CorporationDocument scanner with gravitational registration
US6101283 *24 Jun 19988 Ago 2000Xerox CorporationShow-through correction for two-sided, multi-page documents
US6942213 *26 Mar 200313 Sep 2005Seiko Epson CorporationDuplex scanning device
US796542116 Abr 200821 Jun 2011Xerox CorporationShow-through reduction method and system
EP0570958A1 *19 May 199324 Nov 1993Sharp Kabushiki KaishaA reflective and transmissive original pickup apparatus and a method of reading the original
EP0678787A1 *12 Oct 199425 Oct 1995Hirakawa Kogyo Sha Co., Ltd.Photographing method, and photosensitive material printing apparatus utilizing the same
EP0784396A231 Dic 199616 Jul 1997Xerox CorporationShow-through correction for two-sided documents
EP2337332A2 *13 Dic 201022 Jun 2011Canon Kabushiki KaishaImage reading device for correcting image read from original, method of controlling the image reading device, and storage medium
Clasificaciones
Clasificación de EE.UU.355/23
Clasificación internacionalH04N1/193, H04N1/12, H04N1/00, H04N1/10, G03G15/23, G03B27/52, H04N1/107, G03G15/04, G03B27/48, H04N1/203
Clasificación cooperativaG03G15/23, H04N1/2032, H04N1/0057, H04N1/00718, H04N1/00745, H04N1/193, G03B27/528, G03B27/48, H04N1/203, H04N1/00787, G03G15/04, H04N1/12, H04N1/00734, H04N1/00681, H04N1/0075
Clasificación europeaH04N1/00G4D, H04N1/00G3C, H04N1/00G4B, H04N1/203P, H04N1/00G2E, H04N1/00G6B, G03B27/52P2S, G03B27/48, H04N1/00G, H04N1/00F2, H04N1/203, G03G15/04, G03G15/23
Eventos legales
FechaCódigoEventoDescripción
15 Oct 2004ASAssignment
Owner name: EASTMAN KODAK COMPANY, NEW YORK
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:NEXPRESS SOLUTIONS, INC. (FORMERLY NEXPRESS SOLUTIONS LLC);REEL/FRAME:015928/0176
Effective date: 20040909
19 Jun 2001ASAssignment
Owner name: NEXPRESS SOLUTIONS LLC, NEW YORK
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:EASTMAN KODAK COMPANY;REEL/FRAME:012036/0959
Effective date: 20000717
Owner name: NEXPRESS SOLUTIONS LLC 1447 ST. PAUL STREET ROCHES
30 Ago 1999FPAYFee payment
Year of fee payment: 12
17 Jul 1995FPAYFee payment
Year of fee payment: 8
22 Jul 1991FPAYFee payment
Year of fee payment: 4
11 Ene 1988ASAssignment
Owner name: EASTMAN KODAK COMPANY, ROCHESTER, NY A CORP. OF NJ
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:KLUMPP, ROBERT C.;MESSBAUER, FREDERICK B.;BUCH, DONALD C.;REEL/FRAME:004839/0358;SIGNING DATES FROM 19861111 TO 19861114
Owner name: EASTMAN KODAK COMPANY, A CORP. OF NJ,NEW YORK
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KLUMPP, ROBERT C.;MESSBAUER, FREDERICK B.;BUCH, DONALD C.;SIGNING DATES FROM 19861111 TO 19861114;REEL/FRAME:004839/0358